There exists a widespread utility for filtering/integration. However, there are limitations especially in integration in the prior art including DC offset and saturation. The present invention results in substantial improvement by integrating the circuit output and feeding it back negatively. The resultant DC offset and saturation which plagues other types of active integrators are eliminated. In addition, the circuit gives both the integral and the double integral of the input. A negative feedback feature also gives considerable stability to the circuit.
It is emphasized that the present circuit is a stable filter. Further, the circuit can integrate and double integrate signals having very low frequencies without saturating due to direct current offset on the input. It is noted that the circuit performs the aforesaid without using chopper stabilization or pulse modulation as in the prior art.